In this Dec. 7, 2006 photo, Maj. Gen. Charles Bouchard, left, sits in the cockpit of a DA40 Diamond Star as he listens to Lt. Chevon Smith, in Montego Bay, Jamaica. Canadian Defense Minister Peter MacKay said Friday, March 25, 2011 that Lt.-Gen. Bouchard has been designated to lead the alliance's military campaign in Libya.

NAPLES, Italy — NATO's commander for Libya deflected suggestions Monday that international airstrikes against Moammar Gadhafi's forces were essentially providing air cover for advancing rebels, insisting that NATO's mission is purely designed to protect civilians.

Lt. Gen. Charles Bouchard of Canada told a press conference that the military alliance was in the process of taking over command from the U.S.-led operation after NATO's 28 members agreed Sunday to the transition. He declined to say how long it would take, saying it was complex and still being coordinated, though officials in Brussels have said it would be a few days.

The move effectively means that once the transition is complete, NATO could bomb Gadhafi's forces if they are threatening to harm civilian populations. International airstrikes have crippled Gadhafi's forces, allowing rebels to advance near Gadhafi's stronghold of Sirte after appearing at the brink of defeat.

The U.N. Security Council authorized countries to take all necessary measures to protect civilians in Libya. But critics have said the military campaign goes far beyond what was authorized: On Monday, Russian Foreign Minister Sergey Lavrov said the international air campaign breached the U.N. resolution and amounted to international interference in what he called Libya's civil war.

Asked where NATO drew the line between protecting the civilians and aiding rebels, Bouchard said his mission was clear:

"Our goal is to protect and help the civilians and population centers under the threat of attack," he said.

He declined to elaborate on what his rules of engagement were or how he reconciled NATO's stated mission not to take sides in the conflict, saying only that every decision was designed to limit civilian casualties.

In Brussels, NATO spokeswoman Oana Lungescu noted that the allied operation was launched in response to "the systematic attacks by Col. Gadhafi against his own people."

"That is how this all started, we have to remember that," she said.

She noted that the transition from the U.S.-led force to NATO command would last "a couple of days," and said nations were still assigning military units and equipment to NATO authority.

But a diplomat at NATO headquarters, who spoke condition of anonymity because of the sensitivity of the issue, said most member nations represented in the alliance's governing body had shown little enthusiasm for anything other than the minimal use of force against ground targets.

NATO officials have said the alliance's operations, approved for up to three months, could be extended if necessary.

Several NATO countries have said they would impose conditions — known as caveats — on the use of their air and naval forces. Some, like the Netherlands, have said they will only take part in air patrols but would not participate in attacks on ground targets.

In Afghanistan, NATO commanders have bitterly complained about the existence of national caveats, blaming them for hampering counterinsurgency operations and creating tensions within the alliance.

NATO is assuming full command of the operation as ministers from the alliance and countries outside it head to London on Tuesday to coordinate strategy on Libya. France, which took the early lead in Libya by launching the first airstrikes and giving diplomatic recognition to the rebels, has proposed the creation of a political steering committee to oversee operations .

Asked how any decisions from Tuesday's meeting would affect NATO's chain of command, Bouchard said: "I will be watching it with great interest, and no doubt my commanders will."

In Brussels, Lungescu said the London conference will put in place a steering committee to take over control of the operation from NATO.

"We expect this conference to provide broad political framework to ensure there are guidelines for a peaceful solution in Libya," she said. But she stressed that the North Atlantic Council — NATO's highest decision-making body — "will remain in day-to-day control of military operations in close cooperation with partners in the region."

Lungescu said the conference could put in place an arrangement similar to the Peace Implementation Council used for Bosnia during the Balkan wars in the 1990s.

That council was created in 1995 with the aim of mobilizing international support for the Dayton Peace Agreement that ended the Bosnian War, comprising 55 governments and international agencies. It mainly dealt with economic issues, strengthening Bosnian government institutions and encouraging the return of tens of thousands of refugees and displaced persons.